Keyless chuck for rotary tool

A chuck for a rotary tool comprising:

• a chuck body having a longitudinal axis and connected to a drive spindle of a drive source for driving said chuck body about said axis;
• a jaw unit comprising a set of gripping jaws and means convergingly guiding the jaws for clamping a tool bit to be rotated by said chuck body;
• a sleeve ring disposed around said chuck body and being relatively rotatable with respect to said chuck body, means for displacing said gripping jaws into tool-gripping relation with the tool bit when said chuck body is rotated relative to said sleeve ring in one direction and displacing said gripping jaws out of tool-gripping relation from the tool bit when said chuck body is rotated in an opposite direction relative to said sleeve ring;
• one-way clutch means for releasably engaging said sleeve ring to said chuck body when said chuck body is driven to rotate in said opposite direction such that said sleeve ring rotates together with said chuck body without loosening said gripping jaws and for allowing said chuck body to rotate independently of said sleeve ring in said one direction until said gripping jaws tighten on said tool bit, said one-way clutch means further includes
• (a) ratchet teeth formed on said chuck body for locking said sleeve ring to said chuck body, and
• (b) a pawl supported for pivotal movement about a pivot seated in said sleeve ring and biased by a spring into engagement with said ratchet teeth;
• and
• a handle ring disposed around said sleeve ring and rotatably coupled thereto with a certain amount of play therebetween corresponding to a limited extent, said handle ring having a cam end which is movable into abutment with one end of said pawl to move said pawl out of engagement with said ratchet teeth when said handle ring is caused to rotate within said limited extent relative to said sleeve ring in said one direction against the bias of said spring, said chuck body being freely rotatable relative to said handle ring and sleeve ring in said opposite direction when said one-way clutch is disengaged from said chuck body thereby allowing said drive source to loosen said gripping jaws for removal of the tool bit therefrom by rotating said body in said opposite direction.